D.C.
I am so sorry that you are dealing with this. I've dealt with this same thing for years with my husband and i've tried some of everything. I've tried the nice approach and tried to keep my feelings to myself and then I tried the bad approaches and went off on him every single day of the week. Then i've tried withholding sex from him, I've tried counseling (that I attended alone) then I tried intercepting emails from those women or emailing the women myself and telling them that their actions are inappropriate. Last but not least, I told him I was leaving and he could have his nonsense all to himself.
I can't tell you what will work for you, sometimes all of those things worked and sometimes none of those things worked. I dont' know if you are spiritual at all but I had to take a step back and just pray for the fool. As much as it was killing me to just sit back and take it, I just went about my business and once he realized that I was no longer focused on him, then he decided to show me some attention.
I know you are pregnant and so it may seem like your husband should be completely focused on you and the baby but trust me, I've lived with this man who is the most EMOTIONLESS man i've ever seen in my life. He was extremely mean and uncaring during both of my pregnancies at least that's what it seemed to me. In his mind, he was doing what was necessary to make our family work but in my mind he was a jackass. Saying all that to say, make sure that you have all of your ducks in a row so that if you give him an ultimatum that you are prepared to back it up with whatever it is you say will happen if he doesn't show the love you want.
What I would suggest is that you start doing things on your own. When he gets home, if you feel like cooking then cook otherwise don't cook anything. If you want to watch a movie at night, don't even mention it to him. Go watch it on your own and don't say anything to him. Then if you want to have a romantic dinner or even go out somewhere, call a girlfriend instead of asking him anything. Men like him and my husband respond better when you act like they don't exist. I don't understand why but that's what really worked for me. Now he has to chase me down because 4 out of the 7 days a week I am spending time with a girlfriend and I have sex with him when it's convenient for me. It took a while before I got to this point but it's really liberating. It will be hard for you to do this and you may fall off the wagon a few times but trust me, it really works when you act like they are secondary to your agenda.
As far as the flirting thing, what i've come to realize is that it doesn't matter how good a wife you are, if a man is going to cheat or act inappropriate then they are going to do it regardless of what you say or do. He has to feel like he's losing something at home if he flirts or even thinks about another woman. My husband is still a little more friendly with other women than I would like him to be but I've started dressing up more, wearing more makeup, keeping my hair done and doing more things for myself and he's been more focused on that than trying to have emotional connections with other women. Sorry for babbling, you can email me if you like, I really have had tons of experience with this and I am sorry again that you have to go through this.